U.S. Navy shipyards are continuously involved in periodic overhaul of Navy ships. A major overhaul function is to refurbish valve seats which requires many grinding operations. One such valve seat is the 5" valve seat in a submarine hull. The previous method of refurbishing such a valve seat was to use a lapping plate. After charging the lapping plate with a lapping compound the plate is manually operated in figure eight manipulations on the valve face. After a series of hand manipulations the lapping compound is cleaned away and the lapping plate is recharged with new lapping compound for another series of hand manipulations until a smooth surface is obtained across the entire valve face. This operation is very cumbersome and time consuming. Also the location of some valve seats requires the operator to perform the operation from a very awkward position. Invariably the operator endures extreme fatigue and boredom from the repetitious hand lapping steps.